Quote from: Mulletron on 11/14/2014 09:30 pmSo I need a copper cavity. Those aren't easy to come by and I'm too lazy to buy copper sheet to build my own and I'd probably build it like crap anyway. But I remembered that I can get my hands on a little brass bell just about anywhere. Look in your Christmas decorations. Once a suitable bell is found, it is a straight forward exercise to drill a hole in it to mount an rf connector, fabricate a suitable loop probe and solder it into the rf connector cup, glue some dielectric material in it, and then cut out a copper sheet and solder the thing shut. A quick and dirty resonant cavity on the cheap.For the cavity itself, metal 3d printing is now ubiquitous and affordable.http://gpiprototype.com/services/metal-3d-printing.htmlhttps://www.solidconcepts.com/technologies/direct-metal-laser-sintering-dmls/?gclid=CMCy2rWzmMECFQqCfgod3A4AXw(and many others)A simple CAD design and a submission to a 3d printing company can yield a well-formed prototype cavity within 1-2 weeks. The prototype can be formed of a variety of metals. The prototype could be tested in a non-superconducting configuration first to get a baseline. Then, the inner portion of the cavity could be lined with YBCO film, cooled to liquid nitrogen temperatures, and tested in a superconducting configuration.It even appears that some universities have access to 3d printers that are capable of printing using superconducting materials. Perhaps this would make a good senior project or thesis for an ambitious student. I always wished I'd taken more advantage of my university's resources when I had the chance.http://www.tamuk.edu/engineering/departments/mien/3D%20Printers/index.html
So I need a copper cavity. Those aren't easy to come by and I'm too lazy to buy copper sheet to build my own and I'd probably build it like crap anyway. But I remembered that I can get my hands on a little brass bell just about anywhere. Look in your Christmas decorations. Once a suitable bell is found, it is a straight forward exercise to drill a hole in it to mount an rf connector, fabricate a suitable loop probe and solder it into the rf connector cup, glue some dielectric material in it, and then cut out a copper sheet and solder the thing shut. A quick and dirty resonant cavity on the cheap.
...it is the DIY vs. the Institutional mindset. I remember my high school teacher using liquid nitrogen in the classroom near students to freeze and smash banana peels into bits.
... it would be more a matter of making sure the test article doesn't take off.
I think he’s right. He doesn’t understand. This is a very high Q resonator. The higher the Q, the narrower the bandwidth it can resonate at. Without resonance the Q will drop off to between 1/100 and1/10,000 what it is normally. The resonator needs to resonate. You cannot simply sweep a resonator and think you are changing the frequency only, when the Q is only for small bandwidths of specific frequencies.
Since Eagle has a PLL resonance matching circuit, there is little trouble with this except that you need to note you have not one but two variables as you have changed the amount of active mass.
….you need to note that you have not one but two variables, as you have changed the amount of active mass.
This is much more difficult and much more expensive than you understand. Just the high speed auto matcher used up at George Hathaway’s lab cost $150k. And make no mistake, it is the power equipment that one presumes should be easy enough to build that costs so much. It was a big breakthrough for Eagle to get their PLL circuit in place and this is something that Woodward has never been able to do.
Quote from: DIYFAN on 11/15/2014 07:24 pmIf a resonant frequency can be found with a small superconducting test article, it won't be a matter of detecting tiny force measurements on a delicate balance. If Shawyer type predicted forces bear out, then it would be more a matter of making sure the test article doesn't take off.I should note too, that YBCO's superconductivity is highly frequency dependent. I don't think it works past low VHF. Certainly not microwave.
If a resonant frequency can be found with a small superconducting test article, it won't be a matter of detecting tiny force measurements on a delicate balance. If Shawyer type predicted forces bear out, then it would be more a matter of making sure the test article doesn't take off.
Quote from: Ron Stahl on 11/15/2014 03:14 pmQuoteHave you worked with microwave before?Lol yes. I know what I'm doing. Radars and satcom are what I do. The biggest issue here is trying to couple rf from a 40 pound sweep generator to the test article because of the cable strain. Rf cables are heavy and rigid and using them would screw everything up. If I can't figure this out, I'm not doing it. I'd rather have a small rf generator balanced right there on the thing, running on batteries, but I'm not spending money buying one. I want to use an actual sweep generator so I can tune it and provide an rf sweep. But the cable issue is daunting. I'm thinking of using an xbee pro or putting an old wifi access point in CW mode. I have those. The best I can get in any case is +20dbm, so the test article needs to be small and light. The low powers involved would mean keeping the thing running for hours or days to see if any rotation happens.
QuoteHave you worked with microwave before?
Have you worked with microwave before?
Quote from: Mulletron on 11/15/2014 06:25 pmQuote from: Ron Stahl on 11/15/2014 03:14 pmQuoteHave you worked with microwave before?Lol yes. I know what I'm doing. Radars and satcom are what I do. The biggest issue here is trying to couple rf from a 40 pound sweep generator to the test article because of the cable strain. Rf cables are heavy and rigid and using them would screw everything up. If I can't figure this out, I'm not doing it. I'd rather have a small rf generator balanced right there on the thing, running on batteries, but I'm not spending money buying one. I want to use an actual sweep generator so I can tune it and provide an rf sweep. But the cable issue is daunting. I'm thinking of using an xbee pro or putting an old wifi access point in CW mode. I have those. The best I can get in any case is +20dbm, so the test article needs to be small and light. The low powers involved would mean keeping the thing running for hours or days to see if any rotation happens.Bob Ludwick sent me this response:From: Robert LudwickSent: Saturday, November 15, 2014 5:19 PMTo: Dr. J. RodalIn order to stop worrying about how to install a signal cable from the 40 lb sig gen, plugged into the wall, to the amplifier driving the thruster, forget the cable. The sig gen, which puts out +10-+20 dBm, has plenty of beans to drive something like a standard gain horn transmit antenna, and get enough power across a short gap to a lightweight receive antenna on the test rig to drive the power amplifier to saturation. If not, a low power, low noise pre-amp can be hooked to the receive antenna to boost the power up enough to drive the power amp. Suitable preamps are readily available. And cheap. If one chooses to run the system off a battery, one will be forced to choose between run time and drive power.If one chooses to power the system through some sort of low drag contacts, then 20-30 watt amplifiers are readily available covering the range of frequencies that have been discussed/tested, and run time can be essentially infinite. The devil is in the details, as always, but replacing the stiff RF cable with a short transmit/receive link will at least solve that problem. Bob
I think it is a little too small (higher frequency). I'm trying to stay between 2400-2500mhz.
I gotta figure out how to explain to my boss why I really really need to borrow an expensive 83752B sweep generator for a science experiment in my basement.
I wonder if a light enough "carousel" mounted on a sapphire cup bearing...
Shawyer discloses using YBCO film both in his patent application and in reported prototype testing, with positive results.
What is needed more than ever is additional confirmation of the effect.
...validation does not require a bunch of home hobbyists look to produce results in the garage with chewing gum...
There might be a neighborhood machine shop with a spinning lathe and the skills to use it.
Quote from: DIYFAN on 11/15/2014 08:21 pmShawyer discloses using YBCO film both in his patent application and in reported prototype testing, with positive results.I'll be interested to learn about that, but you need to remember that he had full funding for many years, including those when he won his patent; and he was defunded by the UK because he doesn't have anything and because his notions betray a complete lack of understanding of what group velocity is all about. He is an engineer, not a physicist, and he does not have a real understanding of the concepts he based the device on. If it is working, it is working by mistake and for reasons other than what Shawyer hoped, since what he hoped for was a violation of conservation.